Don't we have WoB that healing depends, at least to some extent, on the person's self-visualization of who they are? Examples of this are:
- The Lopen's arm healing - he never truly accepted losing the arm as part of him.
- Renarin's eyes healing - again, never accepted that as part of himself, alluded to by Kaladin's criticism of him not wearing his glasses anymore as him trying to fit in with Bridge Four.
- Kaladin's scars not healing. To Kaladin, they're part of his identity and the slave is still a part of him. I imagine at some point, perhaps when the 4th or 5th oath is spoken, we'll see these scars healed.
I think Dalinar's wounds were healed or at least helped in the healing process by stormlight, but since he was completely unaware of this, his mind still expected scars to be formed. Thus we get lots and lots of scarring without the complete inability to function because of it.
I think Dalinar has probably been using stormlight subconsciously for quite awhile. Probably at least as long as he's had the Highstorm visions, maybe quite a bit longer.
Off topic a bit, I think surgebinding has a great deal to do with the cognitive aspect of things; with your intentions, your imagination, and your connection to your spren (a cognitive being). So stormlight healing, and its limits, being so dependent upon how the user views his/herself cognitively makes a lot of sense.
